A bonded magnet comprising a shaped solid body of rare earth magnet powder bonded with a binder resin exhibits very high magnetic characteristics and at the same time has a high degree of freedom in shape and the like. Therefore, such bonded magnets are expected to be used in various kinds of devices, such as electric appliances and automobiles which are desired to achieve energy saving and weight reduction.
However, in order to increase the use of the bonded magnets, the bonded magnets are needed to exhibit stable magnetic characteristics even in a high-temperature environment. Therefore, earnest research and development is carried out to improve coercivity of bonded magnets or rare earth magnet powders these days.
The present research and development is just at such a level to add or diffuse dysprosium (Dy), gallium (Ga) and the like to rare earth magnet powder to improve its coercivity. However, Dy, Ga and the like are very scarce elements and use of these elements has a lot of problems in view of stable securement of resources, cost reduction and so on. Therefore, a method for improving coercivity of rare earth magnet powder while suppressing the use of scarce elements has been looked for.